scholarly journals Parametric Simulations on Leakage and Performance of a Miniature Free-Piston Generator (MFPG)

2021 ◽  
Vol 11 (16) ◽  
pp. 7742
Author(s):  
Saifei Zhang ◽  
Chunhua Zhang ◽  
Yong Liu ◽  
Wei Wu ◽  
Han Wu ◽  
...  
Keyword(s):  
Combustion Engine ◽  
Electric Energy ◽  
Voice Coil Motor ◽  
Electrical Equipment ◽  
Energy Conversion Efficiency ◽  
Small Scale ◽  
Portable Devices ◽  
Free Piston ◽  
Heat Engines ◽  
And Performance

The miniaturization of electrical equipment and popularization of portable devices is an appealing motivation for the development of small-scale heat engines. However, the in-cylinder charge leaks severely as the engine dimension shrinks. The free-piston engine on a small scale provides better sealing than other miniature heat engines. Therefore, a miniature free-piston generator (MFPG) with a single-piston internal combustion engine (ICE) and a voice coil motor (VCM) was proposed in this work. A dynamic model with special attention on the heat transfer and leakage was established accordingly, upon which parametric studies of leakage and its effects on the performance of the MFPG system were performed. Four key parameters, including scavenging pressure, ignition position, combustion duration and piston mass, were considered in the model. The results showed that the mass leakage during the compression decreases with the rise of the motoring current. The indicated thermal efficiency can be improved by boosting scavenging pressure and increase motoring current. The critical ignition position is 2 mm before the top dead center. When ignition occurs later than that, the MFPG system is incapable of outputting power. The chemical to electric energy conversion efficiency is about 5.13 %, with an output power of 10~13 W and power density around 4.7~5.7 W/cc.

Current progress and performance improvement of Pt/C catalysts for fuel cells

2020 ◽  
Vol 8 (46) ◽  
pp. 24284-24306
Author(s):  
Xuefeng Ren ◽  
Yiran Wang ◽  
Anmin Liu ◽  
Zhihong Zhang ◽  
Qianyuan Lv ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Energy Conversion ◽  
Performance Improvement ◽  
Electric Energy ◽  
Energy Conversion Efficiency ◽  
High Energy ◽  
Carnot Cycle ◽  
High Energy Conversion Efficiency ◽  
And Performance

Fuel cell is an electrochemical device, which can directly convert the chemical energy of fuel into electric energy, without heat process, not limited by Carnot cycle, high energy conversion efficiency, no noise and pollution.

Investigation of a MEMS-Based Boiler and Free Piston Expander for Energy Harvesting

2012 ◽  
Author(s):  
C. Champagne ◽  
L. Weiss
Keyword(s):  
Dynamic Testing ◽  
Waste Heat ◽  
Maximum Velocity ◽  
Operating Conditions ◽  
Small Scale ◽  
Operational Parameters ◽  
Piston Motion ◽  
Free Piston ◽  
Static Test ◽  
And Performance

Initial investigations of a small-scale Free Piston Expander (FPE) are presented. In final form, the FPE will be a MEMS-based device capable of operation from low temperature waste heat sources. In this present study, a millimeter scale device is constructed and tested to yield insight into critical operational parameters. Different constructions and operating conditions are considered as are the effects on basic piston motion and performance. These include piston length and mass. In addition, different sealing and lubricating fluids are considered. Construction of this testbed device is via concentric copper tubing, allowing an effective baseline study of these determining parameters. Results show that, while thick lubricants seal well in a static test, piston motion is decreased in a dynamic test indicating leakages. By contrast, reduced viscosity lubricants dont seal as well in a static test, but yield increased piston motion in dynamic testing. This indicates effective sealing. The trends established by the study of varying viscosity lubricants hold true for pistons of increasing mass and length as well. A mixture of isopropanol and water performed well in these tests, and represented a low viscosity sealing fluid. Compared to conditions where no lubricant was used, maximum velocity was increased up to 50%. These results indicate that a thin, wetting fluid will be the best lubricant for the FPE, due to increased sealing and performance when in dynamic operation.

scholarly journals THE STARTING PROCESSES OF A CAR ENGINE USING CAPACITIVE ENERGY STORAGES

2019 ◽  
Vol 16 (33) ◽  
pp. 877-888
Author(s):  
R., MALEEV ◽  
S. M. ZUEV ◽  
A. M. FIRONOV ◽  
N. A. VOLCHKOV ◽  
A. A. SKVORTSOV
Keyword(s):  
Energy Storage ◽  
Internal Combustion Engine ◽  
Combustion Engine ◽  
Electric Energy ◽  
Electrical Equipment ◽  
Internal Combustion ◽  
Energy Storage Devices ◽  
Capacitive Energy Storage ◽  
Storage Devices ◽  
Start Up

The article presents data on experiments related to the start-up process of an automobile engine using capacitive energy storage. It is shown that capacitive energy storage devices can be used for efficient start-up of an internal combustion engine. The aim of the article was to study the systems of electric start of vehicles combustion with capacitive energy storage as source of electric energy using a mathematical apparatus that allowed analyzing the process of starting a vehicle engine with capacitive energy. In the course of work, analytical dependences on the time and angle of rotation of the crankshaft of the internal combustion engine (number of working strokes) of the main parameters of the electric starter starting system with a constant moment of resistance on the shaft of the internal combustion engine were obtained. Mathematical calculations and simulation of operating modes in specialized software products were carried out. The results of the experiment showed that the process of scrolling the internal combustion engine with an electric starter when it is powered from capacitive energy storage devices differs significantly from the process of scrolling when powered from a rechargeable battery. Due to the large proliferation of batteries in vehicles and the search for alternative technological solutions to them, it can be said that the results obtained in this article are of practical value in the framework of modern electrical equipment technology.

Design of an External Combustion Engine and its Application in a Free Piston Compressor

2007 ◽  
Vol 3 ◽  
Author(s):  
Jonathan Hogan Webb
Keyword(s):  
Combustion Engine ◽  
Piston Compressor ◽  
Dead Volume ◽  
Transfer Energy ◽  
Free Piston ◽  
Combustion Gases ◽  
Intermediate Chamber ◽  
Fuel Mixtures ◽  
External Combustion ◽  
External Combustion Engine

The design of a free piston compressor and an analysis on integrating an external combustion engine into the compressor design are presented in this article. A free piston compressor is a device which converts chemical energy to work on a volume of air through the kinetic energy of an inertia driven piston, which is not rigidly attached to a ground. An external combustion engine serves as in intermediate chamber which transfers combustion gases to a device to perform some work. The following discusses the design and experiments on an external combustion engine, with a focus on eliminating an injection holding force on a free piston compressor’s elastomeric membranes. The efficiency of the external combustion engine to transfer energy without significant losses due to heat, dead volume, air/fuel mixtures, and actuated valve speed are also presented.

scholarly journals Solid Form and Phase Transformation Properties of Fexofenadine Hydrochloride during Wet Granulation Process

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 802
Author(s):  
Suye Li ◽  
Hengqian Wu ◽  
Yanna Zhao ◽  
Ruiyan Zhang ◽  
Zhengping Wang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Transformation ◽  
Water Content ◽  
Scale Up ◽  
Small Scale ◽  
Dissolution Behavior ◽  
Wet Granulation ◽  
Water Addition ◽  
Granulation Process ◽  
And Performance

The quality control of drug products during manufacturing processes is important, particularly the presence of different polymorphic forms in active pharmaceutical ingredients (APIs) during production, which could affect the performance of the formulated products. The objective of this study was to investigate the phase transformation of fexofenadine hydrochloride (FXD) and its influence on the quality and performance of the drug. Water addition was key controlling factor for the polymorphic conversion from Form I to Form II (hydrate) during the wet granulation process of FXD. Water-induced phase transformation of FXD was studied and quantified with XRD and thermal analysis. When FXD was mixed with water, it rapidly converted to Form II, while the conversion is retarded when FXD is formulated with excipients. In addition, the conversion was totally inhibited when the water content was <15% w/w. The relationship between phase transformation and water content was studied at the small scale, and it was also applicable for the scale-up during wet granulation. The effect of phase transition on the FXD tablet performance was investigated by evaluating granule characterization and dissolution behavior. It was shown that, during the transition, the dissolved FXD acted as a binder to improve the properties of granules, such as density and flowability. However, if the water was over added, it can lead to the incomplete release of the FXD during dissolution. In order to balance the quality attributes and the dissolution of granules, the phase transition of FXD and the water amount added should be controlled during wet granulation.

Stirling Engine Technology for Parabolic Dish-Stirling System Based on Concentrating Solar Power (CSP)

2015 ◽  
Vol 785 ◽  
pp. 576-580 ◽  
Author(s):  
Liaw Geok Pheng ◽  
Rosnani Affandi ◽  
Mohd Ruddin Ab Ghani ◽  
Chin Kim Gan ◽  
Jano Zanariah
Keyword(s):  
High Efficiency ◽  
Combustion Engine ◽  
Renewable Energy Sources ◽  
Stirling Engine ◽  
Energy Sources ◽  
Heat Engines ◽  
Stirling Engines ◽  
Parabolic Dish ◽  
Mechanical Devices ◽  
And Control

Solar energy is one of the more attractive renewable energy sources that can be used as an input energy source for heat engines. In fact, any heat energy sources can be used with the Stirling engine. Stirling engines are mechanical devices working theoretically on the Stirling cycle, or its modifications, in which compressible fluids, such as air, hydrogen, helium, nitrogen or even vapors, are used as working fluids. When comparing with the internal combustion engine, the Stirling engine offers possibility for having high efficiency engine with less exhaust emissions. However, this paper analyzes the basic background of Stirling engine and reviews its existing literature pertaining to dynamic model and control system for parabolic dish-stirling (PD) system.

Investigation on the Combustion and Performance Characteristics of a DI Free Piston Linear Generator Engine fuelled with CNG-CO2 Blend

2021 ◽  
pp. 117441
Author(s):  
Wasiu B. Ayandotun ◽  
A. Rashid A. Aziz ◽  
Zainal A.B.A. Karim ◽  
Salah E. Mohammed ◽  
Ezrann Z. Zainal A. ◽  
...  
Keyword(s):  
Performance Characteristics ◽  
Free Piston ◽  
Linear Generator ◽  
And Performance
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